This work aims to compare the construction of magnification devices. Details of the construction and use of microscopes based on webcam and smartphone are presented, using software for image processing. It is also presented the construction of microscopes using drops of different liquids as magnifying lens, a compound microscope, and a water-drop projector. Magnified images obtained with each device are presented, and the different microscopes are compared. The results obtained from the use of these alternative instruments confirm that alternative microscopes are instruments of easy reproducibility, enabling the amplification of samples for a more detailed observation of the object of interest. devices processing lens microscope waterdrop water drop projector compared reproducibility interest

Renewable resources are alternatives to fossil fuels and pyrolysis is identified as a process for the generation of biofuel products. The lignocellulosic sorghum is a cereal produced in brazil and it presents several applications, such as the production of second-generation ethanol. The present work aimed to study the slow pyrolysis of lignocellulosic sorghum, the biomass was characterized by means of proximate, ultimate, composition and carbohydrate analyzes. Thermogravimetric analyzes were performed with heating rates between 5 and 25 K min-1 and with N2 atmosphere. The Friedman model allows obtaining the kinetic parameters of biomass decomposition and is widely used due to its simplicity and precision; however, since it is sensitive to experimental noise, an algorithm was developed for the calculation of kinetic parameters for the slow pyrolysis of this biomass, enabling an accurate analysis of the experimental data. The activation energy found by the proposed methodology was 122.65 ± 19.24 kJ mol-1, with determination coefficients above 0.97. The comparison between experimental and theoretical data presented deviation values of 0.934%, 3.408% and 1.101% for heating rates of 5, 10 and 15 K min-1, respectively, showing the accuracy for the determined kinetic parameters.

Thermal decomposition of coffee husks was investigated by thermogravimetric analyses. The proximate, ultimate and composition analyses were performed. Thermogravimetric tests were realized, the material was heated to 1173 K using five heating rates: 5, 10, 15, 20, 25 K min-1. The kinetic parameters were estimated using the methods of Kissinger-Akahira-Sunose and Friedman, the distributed activation energy model and the independent parallel reactions model. The isoconversional models of Kissinger-Akahira-Sunose and Friedman showed the dependence between determined values of activation energy and mass conversion, the activation energy values varied from 1437.39 to 199.22 kJ mol-1 for Kissinger-Akahira-Sunose and from 127.81 to 230.35 kJ mol-1 for Friedman model. The values of activation energy were determined for Miura-Maki method; varying from 137.39 to 199.22 kJ mol-1. The model of parallel and independent reactions showed the presence of six different reactions (with activation energy values varying from 42.0 to 214.2 kJ mol-1) occurring during coffee husks pyrolysis, indicating a complex reaction. Currently, works regarding the determination of kinetic parameters for coffee husks pyrolysis are not common. The present work is the first report using the model of parallel and independent reactions to estimate kinetic parameters for pyrolysis of coffee husks, a residue widely generated worldwide.

Cancer constitutes the second main mortality cause in the world, after cardiovascular diseases. In spite of the progresses in the chemotherapeutics treatments, many patients fail chemotherapy, mainly because of side effects or multi-drugs resistance, proving the need and importance of the research for new molecules with anticancer activity, more effective and with smaller adverse effects. Various compounds derived from plant secondary metabolites are commonly used in the chemotherapy against cancer and the natural products play an important role in the research for new molecules. Among several molecules of natural origin evaluated by MTT assay in murine tumor cell lines [breast (LM3) and lung (LP07)] the quinona-methide triterpenes tingenone and pristimerin showed marked cytotoxic activity presenting IC50 around 2 and 5 µM respectively. The structure-activity relationship suggests that rings A and B containing an α, ß-unsaturated carbonyl group are essential for the observed cytotoxic activity. The interaction between these positions and acetylcisteyne residues suggests a probable mechanism of action. The in vitro mutagenic activity was also evaluated by the Salmonella microsome assay (Ames test) for pristimerin and tingenone with and without metabolic activation (S9) in the strains TA98, TA97a, TA100 and TA102, none of which showed mutagenic potential in any strains. Estrogenic and anti-estrogenic activities were also studied by the e-screen assay in MCF-7 cells with negative results. The present data point to the importance of pristimerin and tingenone as representative of an emerging class of potential anticancer chemicals.